氮钾协同减量施肥对甘薯产量品质及土壤养分的影响OA

In response to the issues of rising production costs and non-point source pollution caused by excessive application of nitro-gen(N)and potassium(K)fertilizers in current sweet potato production,the effects of synergistic N and K reduction on sweet potato growth,yield,quality,and soil nutrients under sandy loam conditions were investigated.The aim was to provide a theoretical basis for the green and efficient development of the regional sweet potato industry.A two-factor completely randomized block design was em-ployed.Three N application rates(N1:180 kg·hm-2,N2:162 kg·hm-2,N3:144 kg·hm-2)and three K application rates(K1:120 kg·hm-2,K2:114 kg·hm-2,K3:108 kg·hm-2)were set,with the conventional fertilization rate(N1K1)as the control,resulting in nine treatments with three replicates.Agronomic traits,yield components,nutritional quality,and soil available nutrients were measured,and variance analysis was conducted to reveal the N-K interaction effects.The results showed that Nitrogen fertilizer was the core lim-iting factor for vine growth and fresh tuber yield.Compared with N1,the N2 treatment resulted in an average decrease in fresh tuber yield of only 0.98%,which was not statistically significant under most K levels,indicating that moderate N reduction(10%)is feasible in sandy loam soils.Potassium fertilizer exhibited differential regulatory effects on quality;compared with K1,the K2 treatment in-creased starch content by 10.84%significantly,while soluble sugar,protein,and VC contents decreased by only 4.71%,2.56%and 2.53%,respectively.Compared with N1K1,the N2K2 treatment reduced soil alkali-hydrolyzable N,available K,and available P by 29.5%,18.0%,and 26.2%,respectively,effectively mitigating nutrient surplus.Overall,the N2K1 treatment achieved the highest commercial tuber rate(84.16%),whereas the N2K2 treatment demonstrated a balanced performance among yield,quality,and soil nu-trients.In conclusion,the recommended optimal N and K application rates are 162 kg·hm-2 for N(a 10%reduction compared to con-ventional practice)and 114 kg·hm-2 for K(a 5%reduction).This scheme maintains stable fresh tuber yield and optimizes starch ac-cumulation while significantly reducing residual soil nutrients.It achieves the synergistic goals of fertilizer reduction,efficiency en-hancement,and sustainable soil utilization,thereby providing technical support for regional green sweet potato production.